replaces forgotten tao_attr_search by tao_camera_config_try_find_attr

Solves this crash (with yorick client):

> zyla = tao_attach_remote_camera("zyla")
> h_show,tao_get_members(zyla)
/home/xao/local_tao/libexec/yorick/bin/yorick: symbol lookup error: /home/xao/local_tao/libexec/yorick/lib/ytao.so: undefined symbol: tao_attr_search
$

Tested sucessfully after modification.